Chapter 6: Dominatin Life in Water - The Major Radiation of Fishes

Question 1

What are the two major groups of bony fish?

Answer 1

Ray-finned fish (actinopterygians)

Lobe-finned fish (sarcopterygians)

Question 2

What is the Devonian also known as?

Answer 2

The Age of Fishes because all major lineages of fishes coexisted

Question 3

True or false

Bony fish don’t have a gas-filled bladder

Answer 3

FALSE

They do

Question 4

What are Dipnoi?

Answer 4

Lungfishes

Question 5

Define paedomorphosis

Answer 5

The appearance of juvenile characters in an adult

Question 6

True or false

Ray-finned fishes represent the largest radiation of vertebrates

Answer 6

True

Question 7

True or false

Actinopterygians enlarge their forebrain

Answer 7

True

Question 8

Why do Actinopterygians enlarge their forebrain?

Answer 8

The combination of a small head size and large eyes may create space-packing problems within the developing head, resulting in their inside-out, large brain development

Question 9

Why was their a reduction in the heavy armor of Ray-finned fish?

Answer 9

They had more mobile fins which meant they had more versatile locomotion which increased their ability to avoid predators, thus the need to be light

Question 10

What is the gill cover called?

Answer 10

Operculum

Question 11

Why is suction important in prey capture in water?

Answer 11

A rapid approach by a predator pushes a wave of water in front of its head toward the prey

Question 12

True or false

Teleosts have great mobility in the skeletal elements that rim the mouth

Answer 12

True

Question 13

Why do teleosts have the mobility of the mouth?

Answer 13

It allows the grasping margins of the jaws to be extended forward from the head, often at remarkable speed protrusible jaws

Question 14

True or false

Protrusion helps in gripping prey

Answer 14

True

Question 15

How do fish swim?

Answer 15

Swimming results from anterior-to-posterior contractions of the muscle segments along one side of the body and simultaneous relaxation of those of the opposite side

Question 16

Where does most of the power for swimming come from?

Answer 16

Muscles in the posterior region of the fish

Question 17

What must fish do to be able to swim?

Answer 17

They must overcome the downward pull of gravity and the drag of water. In order to do this they generate vertical lift (a lot do this by generating buoyancy with a gas-filled swim bladder)

Question 18

What is viscous drag affected by?

Answer 18

Surface smoothness

Question 19

What is inertial drag affected by?

Answer 19

Body shape

Question 20

What are the two major life zones in the sea?

Answer 20

1) Pelagic (where organisms live a free-floating or swimming existence)
2) Benthic (where organisms associate with the bottoms either near shore or at great depths)

Question 21

What depth is sunlight totally extinguished?

Answer 21

1000 meters

Question 22

True or false

Fish increase in abundance, size, and species diversity at great depths

Answer 22

FALSE

They decrease

Question 23

What are the costs and benefits of vertical migration?

Answer 23

Benefits: by rising at dusk, certain fish enter a region of higher productivity where there is more food

Costs: they increase their exposure to predators

Question 24

When do the Osteichthyes appear in the fossil record?

Answer 24

Late Silurian period